The disclosure concerns a method and apparatus for application of radio frequency (RF) power to heat material, and more particularly to such a method and apparatus to heat material contained in a vessel.
“Radio frequency” is most broadly defined here to include any portion of the electromagnetic spectrum having a longer wavelength than visible light. Wikipedia provides a definition of “radio frequency” as comprehending the range of from 3 Hz to 300 GHz, and defines the following sub ranges of frequencies:
NameSymbolFrequencyWavelengthExtremely lowELF3-30Hz10,000-100,000kmfrequencySuper low frequencySLF30-300Hz1,000-10,000kmUltra low frequencyULF300-3000Hz100-1,000kmVery low frequencyVLF3-30kHz10-100kmLow frequencyLF30-300kHz1-10kmMedium frequencyMF300-3000kHz100-1000mHigh frequencyHF3-30MHz10-100mVery high frequencyVHF30-300MHz1-10mUltra high frequencyUHF300-3000MHz10-100cmSuper highSHF3-30GHz1-10cmfrequencyExtremely highEHF30-300GHz1-10mmfrequency
Reference is made to U.S. Pat. No. 5,923,299, entitled, “High-power Shaped-Beam, Ultra-Wideband Biconical Antenna.”